After Muhammed and other Muslims had migrated to Medina in 622, the Quraysh confiscated the belongings they had left behind. During that period of time, caravans were accompanied by military escorts of varying strength.

Due to the hospitality Muhammad received in Medina, the Meccans feared the growing influence of the Muslims and thus were contriving to safeguard their trade routes by eliminating the religion of Islam. The Muslims of Medina were aware of such activities and began to make preparations for self-defense.[2]

In 624, Abu Sufyan was the appointed leader of a large merchant caravan carrying a fortune of the Quraysh's goods to Syria for trade. The caravan was escorted by a force of around 40 or 50 soldiers. Muhammad had learned that the caravan was passing close to Medina en route to Syria and organized a Muslim force of 300 men to intercept it and repossess the goods that the Quraysh had stolen from the Muslims due to their absence in Mecca.

Around this time, it is related that God revealed to Muhammad that his people were now given permission to go after those who had oppressed them, driven them from their homes and confiscated their property (some of which the Quraysh put on this same caravan). However, the Muslim contingent Muhammad had assembled failed to intercept the caravan. They arrived after the caravan had already passed by Medina. Abu Sufyan had learned of the Muslims' plan from scouts he had deployed, and in response, sent a crier to Mecca to rally the Quraysh to arms against the Muslims. The Muslims ended up engaging this Meccan army, a force of around 1000 men, at the plains of Badr several days after they had failed to intercept the caravan. This conflict, the Battle of Badr, ultimately resulted in a Muslim victory. The death of most Quraysh leaders in the battle not only left Abu Sufyan the leader of Mecca, but also marked the fulfillment of the Quranic prophecy in surahAr-Rum 2-4.[2]

Abu Sufyan served as the military leader in the later Meccan campaigns against Medina, including the Battle of Uhud in 625 and the Battle of the Trench in 627, but he could not attain final victory.

Eventually the two parties agreed to an armistice, the Treaty of Hudaybiyyah in 628, which allowed Muslims to make the pilgrimage to the Kaaba.

When the armistice was violated in 630 by allies of the Quraish, Muhammad moved towards liberating Mecca from non-Muslim authority. Abu Sufyan, seeing that the balance had tilted in Muhammad's favour and that the Quraish were not strong enough to hinder the Muslims from conquering the city, travelled to Medina, trying to restore the treaty. No agreement was reached between the two parties and Abu Sufyan returned to Mecca empty handed. These efforts ultimately ensured that the conquest occurred without battle or bloodshed.

Abu Sufyan travelled back and forth between Mecca and Madina, still trying to reach a settlement. According to the sources, he found assistance in Muhammad's uncle, Al-‘Abbas ibn ‘Abd al-Muttalib, though some scholars consider that historians writing under the rule of al-‘Abbas' descendants, the Abbasid Caliphate, had exaggerated al-‘Abbas' role and downplayed the role of Abu Sufyan, who was the ancestor of the enemies of the Abbasids.[3]

Abu Sufyan also fought in the Battle of Yarmouk in 636, in which he lost his second eye. He played a very important role in the war as the chief of staff (نقيب) of the Muslim army. He fought under command of his son, Yazid ibn Abi Sufyan.[5][6]